A secondary diffusion process before glass passivation for unidirectional tvs chip

Abstract

The invention discloses a secondary diffusion process before unidirectional TVS chip glass passivation. The method comprises the following steps: S1 phosphorus diffusion, pre-depositing phosphorus diffusion source on the surface of the silicon chip and diffusing it; S2 boron diffusion, coating by printing Coating and diffusing a boron source on the surface of the silicon wafer to be expanded with boron; S3 texturing increases the surface roughness of the silicon wafer and provides a coating basis for the coating of the protective glue in the subsequent glass passivation process of the silicon wafer. The beneficial effect of the present invention is that the boron diffusion source is printed on the surface of the silicon wafer to be expanded by using the screen printing process, so that the coating process of the silicon wafer liquid source is simplified and the processing cycle is shortened; after the liquid source is coated, the negative pressure diffusion process is adopted, Reduce the back-to-source situation at the edge of the silicon wafer, simplify the diffusion process steps, and improve the diffusion efficiency; the PN junction produced is uniform, which reduces the processing cost of the silicon wafer.

Description

technical field [0001] The invention belongs to the field of silicon wafer manufacturing technology, and in particular relates to a secondary diffusion process before glass passivation of a unidirectional TVS chip. Background technique [0002] Transient (transient) voltage suppression diodes, that is, TVS (Transient Voltage Suppressor) diodes are widely used in various electronic circuit systems, and they are used in conjunction with resistors, capacitors and other components for transient high voltage suppression protection. Unidirectional Transient Voltage Suppressor (Unidirectional TVS) Under normal working conditions, TVS presents a high impedance state to the protected line. When the instantaneous voltage exceeds its breakdown voltage, TVS provides a low impedance path for the instantaneous current. The instantaneous current flowing to the protected components is shunted to the TVS diode, and the voltage across the protected components is limited to the clamped voltage...

AI Technical Summary

Problems solved by technology

[0003] At present, the production of silicon wafers in the industry mostly uses the diffusion process to form a PN junction. At present, the commonly used diffusion process in the industry generally uses paper sources for one-time full diffusion. Since the gap between the silicon wafers increases after the paper source is sintered, the volatile phosphorus source diffuses. Returning to the boron surface causes the PN junction to be uneven and the production cycle is long